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Biomedical subjects

M Coulet

Publications and source records attributed to M Coulet.

At least 37 records · Page 2Linked to original sources
PubMed1985

Histochemical study of epididymal secretions in the lizard, Lacerta vivipara. Localization of lectin-binding sites.

The epididymis of lizards elaborates voluminous secretory granules made of a central core and a peripheral vacuole which in the species Lacerta vivipara contain respectively an insoluble protein (protein H) and a soluble protein (protein L). After their discharge these secretions mix with spermatozoa. In order to detect the presence of carbohydrates in these secretions, lectins isolated from Canavalia ensiformis (con A) and from eleven other plants (lentil, soja, pea, gorse and several mushrooms), conjugated to fluorescein isothiocyanate, have been utilized in light-microscopic histochemical investigations of frozen sections from Lacerta vivipara epididymis. Whereas lectins having affinity for L-fucose, lactose, D-galactose and N-acetyl-D-galactosamine bound to central cores, lectins having affinity to D-glucose, N-acetylglucosamine and chitobiose bound to the peripheral vacuole. D-mannose or D-glucose seem to be present both in central cores and in peripheral vacuoles.

Animals↗
PubMed1985

[Influence of technical factors in the determination of minimal inhibitory concentration by microdilution].

Minimal inhibitory concentrations (MICs) of a new quinolone, norfloxacin, as determined by agar dilution are greater than those found using a liquid dilution micromethod. We report herein an analysis of the various parameters possibly involved in this discrepancy: Mueller-Hinton and BioMérieux, glass or plastic, small or large inoculum, and comparative volumes in which the inoculum (IN) and antibiotic (AB) are presented (1 ml IN + 1 ml AB or 1.5 microliter IN + 50 microliter AB or 50 microliter IN + 50 microliter AB). Volume of the inoculum suspension had a bearing on the results obtained with all three reference strains tested. Norfloxacin MICs for S. aureus 7625 and P. aeruginosa 76110 increased commensurately with the ratio of inoculum volume to antibiotic volume, and vice versa. In contrast, no significant variation was found for E. coli 7624. To evaluate the frequency of this effect, we tested 40 antibiotics on the reference strains, and several antibiotics on savage strains (16 Enterobacteriaceae, 40 Staphylococcus, 12 Pseudomonas and 17 P. aeruginosa). The significance of inoculum and antibiotic volumes was corroborated for some antibiotics. Results most consistent with the reference method were obtained with 50 microliter inoculum and 50 microliter antibiotic solution.

Agar↗
PubMed1984

Nosocomial colonization and infection by Achromobacter xylosoxidans.

Achromobacter xylosoxidans, a bacterial species named in 1971, is often isolated from aqueous environments, but little has been reported about its pathogenicity in humans, its epidemiological pattern, and its susceptibility to antibiotics and antiseptics. We were faced with an epidemic caused by this microorganism for 18 months in an intensive care unit. Two patients had fatal infections and 37 others were colonized. The source was the deionized water of the hemodialysis system. The 46 isolates were identified by comparison with the reference strain A. xylosoxidans ATCC 27061. The characteristic cellular fatty acids of this species were demonstrated by gas-liquid chromatography. The minimal inhibitory concentrations of 27 antibiotics were determined. The isolates were susceptible to only two: moxalactam at 4 micrograms/ml and ceftazidime at 8 micrograms/ml. The minimal bactericidal concentrations of one disinfectant and three antiseptics were: sodium hypochloride, 109 micrograms/ml; chlorhexidine digluconate in ethanol solution, 15 to 125 micrograms/ml; polyvinylpyrrolidone iodine, 750 micrograms/ml; and iodine ethanol, 312 to 625 micrograms/ml.

Alcaligenes↗
PubMed1984

Identification and taxonomy of human and animal leishmanias by lectin-mediated agglutination.

The surface polysaccharides of two strains of lizard leishmanias, of the guinea pig parasite L. enrietti and of nine strains of human leishmanias belonging to the groups mexicana, donovani and tropica were studied by lectin-mediated agglutination. Twenty-three lectins prepared from seeds or from higher fungi carpophores were used. They revealed the presence of L-fucose, N-N'-diacetylchitobiose, alpha-D-glucose, alpha-D-mannose, beta-D-galactose, N-acetyl-D-galactosamine and lactose. We noted a range in the number and variety of lectin receptor sites detectable on the surface of the leishmanias, with the reptiles strains having the fewest sites and the tropica group having the most sites. We were unable to find specific group lectins, but it seems possible to identify a strain within each group by a lectin-binding pattern.

Agglutination↗
PubMed1984

[In vitro activity of ceftizoxime on hospital bacteria. Results of a multicenter study].

The susceptibility to ceftizoxime of all bacterial strains isolated from seven university-affiliated hospitals over one month was tested with disk-diffusion technique. Additionally, the MIC of 1937 strains selected at random was evaluated by the agar dilution method. The majority of Enterobacteriaceae are inhibited at a concentration of less than 1 microgram/ml with a mode MIC varying from 0.008 to 0.12 among the various groups. A few Enterobacter and Citrobacter strains are resistant. Little activity was demonstrated by ceftizoxime on Pseudomonas aeruginosa and Acinetobacter sp. (mode MIC 32 and 8 micrograms/ml respectively). Haemophilus sp. (MIC 0.01-0.03) and Neisseria (MIC less than 0,008-0,016) are very susceptible to the drug. The MIC of methicillin-sensitive strains of Staphylococcus aureus varies from 1 to 4 micrograms/ml ; Enterococci are less susceptible, whereas other Streptococci and Pneumococci have low MICs (less than 0.008-0.025). The susceptibility of anaerobic pathogens varies widely between species, and within species ; MIC ranges from 0.008 to 32 micrograms/ml for Clostridium sp. and 0.25 to 128 micrograms/ml for Bacteroides sp.

Bacteria↗
PubMed1984

[Comparative multicenter study of 2 methods of determining sensitivity to antibiotics. Gel diffusion method and semiautomatic method in fluid ABAC medium].

Susceptibility of 60 bacterial isolates to 15 antibiotics was determined by two methods in three laboratories: 48 Gram negative bacilli and 12 Staphylococci were selected because of "intermediate" susceptibility to at least one antibiotic. Results show a good correlation between the two methods: more than 90% for carbenicillin, cefazolin, cefoxitin, cefamandole, kanamycin, tobramycin, amikacin, erythromycin, pristinamycin and fusidic acid, between 80 and 90% for penicillin G, ampicillin, oxacillin, gentamicin, doxycycline, chloramphenicol, spiramycin and clindamycin, less than 80% for neomycin, tetracycline, minocycline and oleandomycin. Interpretation criteria are different in the two methods for rifampicin, colistin and cotrimoxazole. Between the three laboratories, correlation was 90,3% and 88,6% for disc diffusion method and ABAC system respectively.

Anti-Bacterial Agents↗
PubMed1984

[Multicenter study of the antibacterial activity of a new cephalosporin: CM 40874].

Minimal inhibitory concentrations (MIC) of CM were evaluated on 2 548 bacterial strains isolated in 8 hospitals. CM demonstrated high activity on Enterobacteriaceae, the MIC being less than or equal to 0.125 micrograms/ml for 71% of the 1 362 strains tested, less than or equal to 1 for 99.6%, and less than or equal to 4 for 99.9%. Mode MIC varies little among the different groups of Enterobacteriaceae (from 0.06 to 0.12 micrograms/ml), with the exception of Serratia sp. (mode MIC : 0.25) and Klebsiella oxytoca (mode MIC : 0.03). Most of Enterobacter, Serratia, and Citrobacter sp. strains not inhibited by cefotaxime are readily inhibited by CM at the same concentrations than susceptible strains. CM has less activity on P. aeruginosa (MIC 2-32 micrograms/ml) and Acinetobacter sp. (MIC 8-128). Staphylococci (MIC 32) and Enterococci are not susceptible. Variable activity is found against other Streptococci. CM inhibits Haemophilus sp. at MICs of 0.12 to 0.5 micrograms/ml and Gonococci at MICs of 0.03 to 0.5 (whether the strains produce beta-lactamase or not). Meningococci have a mode MIC of 0.03 micrograms/ml (range 0.008 to 0.25). Thus, CM 40874 is a new third generation cephalosporin with high activity on Enterobacteriaceae, including those strains not susceptible to cefotaxime and good activity on Haemophilus sp. and Neisseria sp. This additional activity is probably supported by enhanced resistance to enzymatic inactivation by beta-lactamases.

Bacteria↗
PubMed1983

Spontaneously acquired factor VIII inhibitor in a non-haemophiliac child.

A three-year-old girl who had for two months suffered bruising after minimal injury was admitted because of diffuse ecchymoses and a large haematoma hindering elbow movement. These symptoms were attributable to the development of antifactor VIII inhibitor. No definite etiology was evident despite repeated immunological investigation. Although the inhibitor still persisted at high levels after two years, no further haemorrhage occurred, excepted haematomas three months after the onset of symptoms, in association with mumps.

Antibodies↗
PubMed1983

[In vitro antibacterial activity of cefmenoxime (SCE 1365)].

617 clinical isolates were tested, 592 of which were from hospital source. The minimal inhibitory concentrations of cefmenoxime were determined by a microtiter dilution method, using Mueller-Hinton broth. The results obtained give a 92% agreement with the reference agar-dilution method. Cefmenoxime shows a potent activity against Enterobacteriaceae (n = 420): the modal MIC is less than or equal to 0,03 mg/l, and 90% of them are inhibited by 1 mg/l. Some isolates require a higher concentration, above 32 mg/l: Enterobacter (8%), indole-positive Proteus (13%), Serratia (3%), Citrobacter (3%). Pseudomonas (n = 71) and Acinetobacter (n = 62) appear to be less susceptible than Enterobacteriaceae. The modal MIC is 16 mg/l and the concentration inhibiting 90% of the isolates is above 32 mg/l. The modal MIC of cefmenoxime against Staphylococcus aureus (n = 64) is 1 mg/l, and 90% of the strains belonging to this species are inhibited by 32 mg/l.

Acinetobacter↗
PubMed1983

[Antibacterial activity of apalcillin against 300 strains of enterobacteria].

The in vitro bacteriostatic activity of apalcillin was compared with those of piperacillin, mezlocillin and carbenicillin. The minimal inhibitory concentrations determined by a microtiter dilution method, show a bi-modal distribution: apalcillin, piperacillin: 1 mg/l - greater than 128 mg/l; mezlocillin: 2 mg/l - greater than 128 mg/l; carbenicillin: 4 mg/l - greater than 128 mg/l. Two thirds of the isolates are inhibited by 8 mg/l of any antibiotic, except carbenicillin (128 g/l). Two genus seem less susceptible: Klebsiella display modal MIC of apalcillin and piperacillin equal to 4 mg/l and above 128 mg/l: Serratia isolates resist to 128 mg/l, whatever antibiotic is considered. The in vitro bactericidal activity of apalcillin was evaluated by killing-curves method against 8 Enterobacteriaceae strains. Used at a concentration equal to the MIC or twice the MIC, apalcillin produces a 1,5-2 log10 reduction in viable count, 3 hours after the addition of antibiotic.

Ampicillin↗
PubMed1983

[Multicenter study of the in vitro antibacterial activity of ceftazidime on gram-negative bacilli].

This work reports a multicenter study of antibacterial activity of ceftazidime, a new third generation cephalosporin, on hospital Gram negative rods. Enterobacteriaceae are very sensitive to ceftazidime with a maximum number of strains inhibited by 1 microgram/ml or less (modal MIC 0, 125 microgram/ml); some resistant strains are observed, particularly among Enterobacter and Citrobacter. Activity of ceftazidime on Pseudomonas aeruginosa is superior to other third generation cephalosporins; modal MIC is 1 microgram/ml and 88% of the strains are inhibited by 4 microgram/ml or less. Acinetobacter are less sensitive to ceftazidime, with a modal MIC of 8 microgram/ml.

Bacteria↗
PubMed1983

[Effect of storage time at -20 degrees C on the determination of serum concentrations of tobramycin in the presence of 6 beta-lactams].

We assessed the role of six beta-lactam antibiotics and of storage time at - 20 degrees C, in inactivation of tobramycin in patients' sera. Several ranges of concentrations were used for the combined antibiotics. The tobramycin concentrations were measured both by microbiological assay (plate diffusion) and an enzyme mediated immunoassay technique (EMIT). Using the bioassay method, the results after 8 days of frozen storage were as follows: carbenicillin and ticarcillin (256 mg/l) induced a 40-50% reduction of tobramycin activity, whereas mezlocillin (256 mg/l) had less effect: a 15-20% reduction. After 15 days at -20 degrees C the results were nearly the same except for azlocillin (256 mg/l), increasing its percentage reduction to 20%. The results obtained by EMIT procedure were significantly better after 8 days of frozen storage: only mezlocillin (5% reduction) and azlocillin (10%) were effective. Nevertheless after 15 days at -20 degrees C, the inactivating action of the pre-cited antibiotics were similar to those obtained at the same time with the bioassay method. Piperacillin and cefsulodin never induced any reduction of tobramycin levels, whatever the time of storage or quantification procedure used. So, our opinion is that patients' sera containing a beta-lactam antibiotic in combination with tobramycin should be assayed immediately upon receipt. Keeping it at -20 degrees C is not sufficient to prevent in vitro tobramycin inactivation.

Anti-Bacterial Agents↗
PubMed1982

[Comparative in vitro activity of dibekacin, gentamicin and tobramycin on 617 bacterial strains].

Minimum inhibitory and bactericidal concentrations of 3 aminoglycosides (dibekacin, gentamicin, tobramycin) have been recorded with 617 hospital strains. 4 mg/l of tobramycin inhibited 82 to 84% of Enterobacteria, Pseudomonas, Acinetobacter and S. Aureus; the less sensitive species are Serratia (51%) and Citrobacter (68%). 4 mg/l concentration of gentamicin or dibekacin inhibited 80-83% of Pseudomonas and S. Aureus, 78-79% of Acinetobacter and 74% of Enterobacteria. Dibekacin shows an in vitro activity superior to that of gentamicin and inferior to that of tobramycin on Klebsiella and Proteus mirabilis, but is rather to that of gentamicin and tobramycin on all other bacteria species.

Anti-Bacterial Agents↗
PubMed1982

Purification and lectins from Ricinus communis by combination of affinity and ion-exchange chromatography and characterization of the isolated proteins.

Lectins in the seeds of Ricinus communis L. were separated by affinity chromatography using stromata, and 3 fractions obtained by ion-exchange chromatography. Polyacrylamide-gel electrophoresis showed that 2 fractions were homogeneous and that 1 fraction gave 2 bands. Immunoelectrophoresis with rabbit antisera and polyacrylamide-gel isoelectric focusing showed that the 3 fractions were separate and distinct entities consisting of many proteins with isoelectric points near the isoelectric point of the main protein. The molecular weights of the separated proteins and their subunits were studied by SDS polyacrylamide-gel electrophoresis.

Animals↗
PubMed1982

Poisoning by Gyromitra : a possible mechanism.

"Gyromitra" are considered to be edible mushrooms although their potential toxicity has been long known. They have caused numerous accidents, sometimes lethal. Historical accounts of poisoning are reported and the authors describe the main characteristics : inconstant toxicity, influence of repetitive ingestions and variable individual sensitivity. Knowing the "gyromitrin" (N-methyl-N-formyl-acetyl-hydrazone) can be converted into methyl-hydrazine, the authors suggest a relation between individual sensitivity to the mushrooms and variation of every body's ability to carry out such a conversion. Several metabolites of gyromitrin can produce enzyme activation ith subsequent synthesis of methylhydrazine. The cumulative activating role of consecutive ingestions is emphasized.

Acetaldehyde↗
PubMed1982

Evaluation of infectious episodes in neonates using a new procedure for the nitroblue tetrazolium test.

A new procedure for the NBT slide test for peripheral blood neutrophils has been tested. 255 neonates were studied of which 63 served as control cases. Among the 114 term infants, 37 were patently infected, 30 suspicious and 47 non-infected. The latter did not significantly differ from control cases, whereas suspicious and infected infants were credited with significantly higher NBT scores. 78 infants were preterm, 31 of which were patently infected, 22 suspicious and 25 non-infected. NBT scores of infected and suspicious infants were significantly higher than those of non-infected infants, but, as previously reported, scores of preterm infants were systematically and significantly lower than those of full-term infants of the same bacteriological class. Threshold values are suggested; they could represent an accurate diagnostic aid in the early differentiation of healthy infants from high-risk infants regarding bacterial infections.

Bacterial Infections↗